Display device

ABSTRACT

In a liquid crystal display device, a second substrate includes a detection electrode of a touch panel, pixels include pixel electrodes and counter electrodes, the counter electrodes are divided into a plurality of blocks, the counter electrodes of the divided blocks are provided in common to the pixels on a plurality of display lines being side by side, the counter electrodes of the divided blocks are used as scanning electrodes of the touch panel as well, the liquid crystal display device includes a semiconductor chip configured to supply a counter voltage and a touch panel scanning voltage to the counter electrodes of the divided blocks, the semiconductor chip includes a first terminal group formed on a side of a display area side configured by the plurality of pixels.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priority from Japanese applicationJP2012-131154 filed on Jun. 8, 2012, the content of which is herebyincorporated by reference into this application.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to a liquid crystal display device and,more particularly, to a technique effectively applied to an in-cell typeliquid crystal display device incorporating a touch panel.

2. Description of the Related Art

A display device including a device (hereinafter also referred to astouch sensor or touch panel) for inputting information by the touchoperation (contact pressing operation, hereinafter simply referred to astouch) using the user's finger, a pen or the like on the display surfaceis used in mobile electronic apparatuses such as a PDA and a portableterminal, various home electric appliances, an automated teller machine,and the like.

As such a touch panel, there is known a capacitance type touch panelthat detects a capacitance change of a touched portion.

As the capacitance type touch panel, as disclosed in JP 2009-258182 A,there is known a liquid crystal display device including a so-calledin-cell touch panel in which a touch panel function is incorporated in aliquid crystal display panel.

In the in-cell touch panel, a counter electrode (also referred to ascommon electrode (CT)) formed on a first substrate (also referred to asTFT substrate) included in the liquid crystal display panel is dividedand used as scanning electrode of the touch panel.

SUMMARY OF THE INVENTION

In general, in the in-cell touch panel, a scanning line driving circuitfor driving a scanning line (a gate line) is normally incorporated inthe inside of the liquid crystal display panel.

As the liquid crystal display panel, there are a liquid crystal displaypanel incorporating a driving circuit configured by an n-type amorphoussilicon thin-film transistor in which an amorphous silicon layer is usedas a semiconductor layer (hereinafter referred to as driving circuithaving the a-Si single channel circuit configuration), a liquid crystaldisplay panel incorporating a driving circuit having a single channelcircuit configuration configured by a polysilicon thin-film transistorin which a p-type or n-type polysilicon layer is used as a semiconductorlayer (hereinafter referred to as driving circuit having the p-Si singlechannel circuit configuration), and a driving circuit having a CMOScircuit configuration including a p-type polysilicon thin-filmtransistor and an n-type polysilicon thin-film transistor in whichp-type and n-type polysilicon layers are used as semiconductor layers(hereinafter referred to as driving circuit having the CMOS circuitconfiguration).

In developing a touch sense function incorporating liquid crystal driverIC adapted to the in-cell touch panel, development costs and adevelopment period increase if the liquid crystal driver IC isseparately developed for each of the liquid crystal display panelincluding the driving circuit having the a-Si single channel circuitconfiguration, the liquid crystal display panel including the drivingcircuit having the p-Si single channel circuit configuration, and theliquid crystal display panel including the driving circuit having theCMOS circuit configuration.

The present invention has been devised in order to solve the problem ofthe related art and it is an object of the present invention to providea technique for enabling a reduction in development costs and areduction in a development period of a liquid crystal driver IC in aliquid crystal display device incorporating a touch panel function.

The object and other objects and new characteristic of the presentinvention are clarified by the description of this specification and theaccompanying drawings.

Overviews of representative inventions among inventions disclosed inthis application are briefly explained below.

(1) A liquid crystal display device including a liquid crystal displaypanel including a first substrate, a second substrate, and liquidcrystal held between the first substrate and the second substrate, theliquid crystal display device including a plurality of pixels arrangedin a matrix shape, wherein the second substrate includes a detectionelectrode of a touch panel, the pixels include pixel electrodes andcounter electrodes, the counter electrodes are divided into a pluralityof blocks, the counter electrodes of the divided blocks are provided incommon to the pixels on a plurality of display lines being side by side,the counter electrodes of the divided blocks are used as scanningelectrodes of the touch panel as well, the liquid crystal display deviceincludes a semiconductor chip configured to supply a counter voltage anda touch panel scanning voltage to the counter electrodes of the dividedblocks, the semiconductor chip includes a first terminal group formed ona side of a display area side configured by the plurality of pixels, anda plurality of terminals arranged on both sides of the semiconductorchip in the first terminal group are terminals for supplying the countervoltage and the touch panel scanning voltage to the counter electrodesof the divided blocks.

-   -   (2) In (1), when the number of divisions of the counter        electrodes is represented as M (1≤M≤24), the plurality of        terminals arranged on both the sides of the semiconductor chip        are M terminals A1 arranged at one end and M terminal s A2        arranged at the other end, and the semiconductor chip can be        switched to a mode for supplying, from each of the plurality of        terminals A1 and the plurality of terminals A2, the touch panel        scanning voltage to the counter electrodes sequentially selected        among the counter electrodes of the divided blocks and supplying        the counter voltage to the counter electrodes other than the        selected counter electrodes and a mode for outputting the        counter voltage from first to Nth (1≤N (e.g., N=M/2)<24)        terminals among the M terminals A1 and the M terminals A2 and        outputting the touch panel scanning voltage from the remaining        Nth to Mth terminals.

(3) in (2), the first substrate includes a plurality of scanning linesfor inputting a scanning voltage to the pixels and a scanning linedriving circuit configured to supply the scanning voltage to theplurality of scanning lines, the scanning line driving circuit is acircuit incorporated in the inside of the liquid crystal display paneland configured using only either n-type or p-type transistor, and thesemiconductor chip supplies, from each of the plurality of terminals A1and the plurality of terminals A2, the touch panel scanning voltage tothe counter electrodes sequentially selected the counter electrodes ofthe divided blocks and supplies the counter voltage to the counterelectrodes other than the selected counter electrodes.

(4) In (2), the first substrate includes a plurality of scanning linesfor inputting a scanning voltage to the pixels, a scanning line drivingcircuit configured to supply the scanning voltage to the plurality ofscanning lines, and a counter electrode selecting circuit configured toselect the counter electrodes of the divided blocks, the counterelectrode selecting circuit is arranged between the scanning linedriving circuit and a display area, the counter electrode selectingcircuit is a circuit incorporated in the inside of the liquid crystaldisplay panel and having a CMOS circuit configuration, and thesemiconductor chip supplies, to the counter electrode selecting circuit,the counter voltage from first to Nth (1≤N<24) terminals among the Mterminals A1 and the M terminals A2 and supplies the touch panelscanning voltage from the remaining Nth to Mth terminals.

(5) A liquid crystal display device including a liquid crystal displaypanel including a first substrate, a second substrate, and liquidcrystal held between the first substrate and the second substrate, theliquid crystal display device including a plurality of pixels arrangedin a matrix shape, wherein the second substrate includes a detectionelectrode of a touch panel, the first substrate includes a plurality ofscanning lines for inputting a scanning voltage to the pixels and afirst scanning line driving circuit and a second scanning line drivingcircuit arranged on both sides of a display area, which are configuredby the plurality of pixels, and configured to supply the scanningvoltage to the plurality of scanning lines, the first scanning linedriving circuit and the second scanning line driving circuit arecircuits incorporated in the inside of the liquid crystal display panel,the pixels include pixel electrodes and counter electrodes, the counterelectrodes are divided into a plurality of blocks, the counterelectrodes of the divided blocks are provided in common to the pixels ona plurality of display lines being side by side, the counter electrodesof the divided blocks are used as scanning electrodes of the touch panelas well, the liquid crystal display device includes a semiconductor chipconfigured to supply a counter voltage and a touch panel scanningvoltage to the counter electrodes of the divided blocks and supply adisplay control signal to the first scanning line driving circuit andthe second scanning line driving circuit, the semiconductor chipincludes a second terminal group formed on a side on the opposite sideof the display area configured by the plurality of pixels, a pluralityof terminals arranged at one end of the semiconductor chip in the secondterminal group are terminals B1 for supplying the display control signalto the first scanning line driving circuit, and a plurality of terminalsarranged at the other end of the semiconductor chip in the secondterminal group are terminals B2 for supplying the display control signalto the second scanning line driving circuit.

(6) In (5), a type of the display control signal supplied from theplurality of terminals B1 to the first scanning line driving circuit anda type of the display control signal supplied from the plurality ofterminals B2 to the second scanning driving circuit are different on thebasis of data set in a register on the inside of the semiconductor chip.

(7) In (5), the liquid crystal display device includes a first counterelectrode selecting circuit and a second counter electrode selectingcircuit arranged on both sides of the display area, which is configuredby the plurality of pixels, and configured to select the counterelectrodes of the divided blocks, the first counter electrode selectingcircuit and the second counter electrode selecting circuit are circuitsincorporated in the inside of the liquid crystal display panel, and theplurality of terminals B1 and the plurality of terminals B2 also includeterminals for supplying an address signal to the first counter electrodeselecting circuit and the second counter electrode selecting circuit.

(8) A liquid crystal display device including a liquid crystal displaypanel including a first substrate, a second substrate, and liquidcrystal held between the first substrate and the second substrate, theliquid crystal display device including a plurality of pixels arrangedin a matrix shape, wherein the second substrate includes a detectionelectrode of a touch panel, the pixels include pixel electrodes andcounter electrodes, the counter electrodes are divided into a pluralityof blocks, the counter electrodes of the divided blocks are provided incommon to the pixels on a plurality of display lines being side by side,the counter electrodes of the divided blocks are used as scanningelectrodes of the touch panel as well, the liquid crystal display deviceincludes a semiconductor chip configured to supply a counter voltage anda touch panel scanning voltage to the counter electrodes of the dividedblocks, the semiconductor chip includes a second terminal group formedon a side on the opposite side of a display area configured by theplurality of pixels, a plurality of terminals arranged in the center ofthe semiconductor chip in the second terminal group are terminals D towhich an input signal group from the outside is input, a plurality ofterminals arranged at one end of the semiconductor chip in the secondterminal group are terminals B1 for supplying the display control signalto the first scanning line driving circuit, a plurality of terminalsarranged at the other end of the semiconductor chip in the secondterminal group are terminals B2 for supplying the display control signalto the second scanning line driving circuit, and terminals C arrangedbetween the terminals D and the terminals B1 and terminals C2 arrangedbetween the terminals D and the terminals B2 are terminals to which adetection voltage from the detection electrode is input.

(9) In (8), either the terminals C1 or the terminals C2 are used, butnot both.

An effect obtained by the representative invention among the inventionsdisclosed in this application is briefly explained below.

With the liquid crystal display device incorporating the touch panelfunction according to the present invention, it is possible to reducemanufacturing costs and reduce a development period of a liquid crystaldriver IC.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded perspective view showing a schematic configurationof a touch panel-attached liquid crystal display device of the relatedart;

FIG. 2 is a plan view showing an electrode configuration of the touchpanel shown in FIG. 1 ;

FIG. 3 is a sectional view showing a sectional structure of the touchpanel shown in FIG. 1 ;

FIG. 4 is an exploded perspective view showing a schematic configurationof a touch panel-incorporating liquid crystal display device;

FIG. 5 is a diagram for explaining counter electrodes and detectionelectrodes in the touch panel-incorporating liquid crystal displaydevice shown in FIG. 4 ;

FIG. 6 is a schematic sectional view showing in enlargement a part ofthe cross section of a display area of the touch panel-incorporatingliquid crystal display device shown in FIG. 4 ;

FIG. 7 is a plan view showing an example of counter electrodes dividedinto a plurality of blocks in an example of a liquid crystal displaydevice applied with the present invention;

FIG. 8 is a plan view for explaining a method of driving counterelectrodes divided into a plurality of blocks in another example of theliquid crystal display device applied with the present invention;

FIG. 9 is a block diagram showing a configuration example of a counterelectrode selecting circuit shown in FIG. 8 ;

FIG. 10 is a circuit diagram showing a circuit configuration of anexample of a selection circuit shown in FIG. 9 ;

FIG. 11 is a circuit diagram showing a circuit configuration of anexample of an address decoder circuit shown in FIG. 9 ;

FIG. 12 is a diagram for explaining driving waveforms during touch paneldetection and during pixel writing in the touch panel-incorporatingliquid crystal display device;

FIG. 13 is a diagram for explaining timings during touch panel detectionand during pixel writing in the touch panel-incorporating liquid crystaldisplay device;

FIG. 14 is a diagram showing a connection example of terminals (A1) of aliquid crystal driver IC in an embodiment of the present inventionconnected when divided counter electrodes are directly driven;

FIG. 15 is a diagram showing a connection example of the terminals (A1)of the liquid crystal driver IC in the embodiment of the presentinvention connected when the counter electrode selecting circuit shownin FIG. 8 is used;

FIG. 16 is a diagram showing a connection example of input sideterminals of the liquid crystal driver IC in the embodiment of thepresent invention;

FIG. 17 is a diagram showing a connection example of terminals (B1 andB2) arranged on an input side of the liquid crystal driver IC in theembodiment;

FIG. 18 is a configuration diagram of the liquid crystal driver IC inthe embodiment in which terminals (C1) on the left side are used; and

FIG. 19 is a configuration diagram of the liquid crystal driver IC inthe embodiment in which terminals (C2) on the right side are used.

DETAILED DESCRIPTION OF THE INVENTION

An embodiment of the present invention is explained in detail below withreference to the accompanying drawings.

In all the figures for explaining the embodiment, components having thesame functions are denoted by the same reference numerals and signs andrepeated explanation of the components is omitted. The embodimentexplained below is not an embodiment for limiting the interpretation ofthe scope of the claims of the present invention.

FIG. 1 is an exploded perspective view showing a schematic configurationof a touch panel-attached liquid crystal display device of the relatedart.

FIG. 2 is a plan view showing an electrode configuration of the touchpanel shown in FIG. 1 .

FIG. 3 is a sectional view showing a sectional structure of the touchpanel shown in FIG. 1 .

In general, the touch panel includes, as shown in FIG. 2 , scanningelectrodes (TX) and detection electrodes (RX) for capacitance detection.For example, three scanning electrodes (TX1 to TX3) are shown as thescanning electrodes (TX) and two detection electrodes (RX1 and RX2) areshown as the detection electrodes (RX). However, the numbers of theelectrodes are not limited to these numbers.

The touch panel includes, as shown in FIGS. 1 and 3 , a touch panelsubstrate 41, the scanning electrodes (TX) and the detection electrodes(RX) formed on the touch panel substrate 41, an interlayer insulatingfilm 42 formed on the scanning electrodes (TX) and the detectionelectrodes (RX), connecting sections (STX) formed on the interlayerinsulating film 42 and configured to electrically connect the scanningelectrodes (TX), a protective film 43 formed on the connecting sections(STX), a front window (or a protective film) 44 arranged on theprotective film 43, and a shield transparent electrode (e.g., anelectrode formed by an ITO (Indium Tin Oxide) film) 45 formed on aliquid crystal display panel side of the touch panel substrate 41.

In the touch panel in the past, a touch panel control IC (DRT)pulse-drives the scanning electrodes (TX) at a voltage of about 5 V to10 V, detects a voltage change in the detection electrodes (RX), anddetects a touch position. That is, a capacitance value between thescanning electrodes (TX) and the detection electrodes (RX) changesbecause of a finger or the like. When the scanning electrodes (TX) arepulse-driven, voltage fluctuation detected by the detection electrodes(RX) changes. Therefore, it is possible to detect the touch position bymeasuring the voltage of the detection electrodes (RX).

The touch panel is set on the front surface of the liquid crystaldisplay panel. Therefore, when a user views an image displayed on theliquid crystal display panel, the displayed image needs to betransmitted through the touch panel. Therefore, the touch paneldesirably has high light transmittance.

The liquid crystal display panel includes, as shown in FIG. 1 , a firstsubstrate (SUB1; hereinafter referred to as TFT substrate), a secondsubstrate (SUB2; hereinafter referred to as CF substrate), and liquidcrystal (not shown in the figure) held between the TFT substrate (SUB1)and the CF substrate (SUB2).

The TFT substrate (SUB1) has an area larger than the area of the CFsubstrate (SUB2). A liquid crystal driver IC (DRV) is mounted on aregion of the TFT substrate (SUB1) not opposed to the CF substrate(SUB2). Further, a main flexible printed circuit board (MFPC) is mountedon a peripheral section of one side of the region.

In FIG. 1 , CT denotes a counter electrode (also referred to as commonelectrode), TFPC denotes a flexible printed circuit board for a touchpanel, CD denotes a rear-side transparent conductive film, 52 denotes aconnecting member, and 53 denotes a connection flexible printed circuitboard.

In an IPS-type liquid crystal display panel, unlike a TN-type liquidcrystal display panel and a VA-type liquid crystal display panel, thecounter electrode (CT) is absent on a substrate on which a color filteris provided. Therefore, for example, to reduce display noise, therear-side transparent conductive film (CD) formed by a transparentconductive film such as an ITO is formed on the substrate on which thecolor filter is provided.

FIG. 4 is an exploded perspective view showing a schematic configurationof a touch panel-incorporating liquid crystal display device in which atouch panel is incorporated in the inside of the liquid crystal displaypanel.

In FIG. 4, 2 denotes a TFT substrate, 3 denotes a CF substrate, 21denotes a counter electrode (also referred to as common electrode), 5denotes a liquid crystal driver IC, MFPC denotes a main flexible printedcircuit board, 40 denotes a front window, and 53 denotes a connectionflexible printed circuit board.

In the liquid crystal display device shown in FIG. 4 , the rear-sidetransparent conductive film (CD) on the CF substrate 3 is divided intobelt-like patterns to form detection electrodes (RX) 31 of the touchpanel. The counter electrode 21 formed on the inside of the TFTsubstrate 2 is divided into belt-like patterns, i.e., a plurality ofblocks and used as scanning electrodes (TX) of the touch panel as wellto reduce the touch panel substrate (41 in FIG. 1 ). Therefore, in theliquid crystal display device shown in FIG. 4 , a function of the touchpanel control IC (DRT) shown in FIG. 1 is provided on the inside of theliquid crystal driver IC 5.

The counter electrode 21 and the detection electrode 31 of the liquidcrystal display device shown in FIG. 4 are explained with reference toFIG. 5 .

As explained above, the counter electrode 21 is provided on the TFTsubstrate 2. A plurality of (e.g., about twenty) counter electrodes 21are connected in common at both ends and connected to a counterelectrode signal line 22.

In the liquid crystal display device shown in FIG. 5 , bundle-likecounter electrodes 21 are used as the scanning electrodes (TX) as welland detection electrodes 31 configure the detection electrodes (RX).

Therefore, a counter electrode signal includes a counter voltage usedfor image display and a touch panel scanning voltage used for detectionof a touch position. When the touch panel scanning voltage is applied tothe counter electrodes 21, detection signals are generated in thedetection electrodes 31 arranged a fixed space away from the counterelectrode 21 to configure capacitors. The detection signals areextracted to the outside via detection electrode terminals 36.

Dummy electrodes 33 are formed on both sides of the detection electrodes31. The detection electrodes 31 expand toward the dummy electrodes 33side at one ends to form T-shaped detection electrode terminals 36.Various wires, terminals, and the like such as driving circuit inputterminals 25 are formed on the TFT substrate 2 besides the counterelectrode signal line 22.

A schematic sectional view in which a part of the cross section of adisplay area in the liquid crystal display device shown in FIG. 4 isenlarged is shown in FIG. 6 .

As shown in FIG. 6 , a pixel section 200 is provided on the TFTsubstrate 2. The counter electrodes 21 are used for image display as apart of pixels. A liquid crystal composition 4 is held between the TFTsubstrate 2 and the CF substrate 3. The detection electrodes 31 providedon the CF substrate 3 and the counter electrodes 21 provided on the TFTsubstrate form capacitors. When a driving signal is applied to thecounter electrodes 21, the voltage of the detection electrodes 31changes.

At this point, as shown in FIG. 6 , when a conductor such as a finger502 comes closer to or comes into contact with the front window 40, achange occurs in capacitance and a change occurs in the voltagegenerated in the detection electrodes 31 compared with the voltagegenerated when the conductor does not come close to or come into contactwith the front window 40.

In this way, the change in the capacitance generated between the counterelectrodes 21 and the detection electrodes 31 formed on the liquidcrystal display panel is detected. Consequently, it is possible toprovide a function of a touch panel in the liquid crystal display panel.

FIG. 7 is a plan view showing an example of the counter electrodesdivided in the plurality of blocks in an example of the liquid crystaldisplay device applied with the present invention. In FIG. 7 , SUB1denotes a TFT substrate, DRV denotes a liquid crystal driver IC, CT1 toCT20 denote the counter electrodes of the blocks divided into belt-likepatterns, DL denotes video lines, CTL denotes counter electrode wires,GES denotes scanning line driving circuits, GTL denotes scanning linedriving circuit signal wires, TAM denotes a terminal section connectedto the main flexible printed circuit board (MFPC), and AR denotes adisplay area configured by a plurality of pixels arranged in a matrixshape.

In the example shown in FIG. 7 , as the scanning line driving circuits(GES), driving circuits having an a-Si single channel circuitconfiguration or driving circuits having a p-Si single channel circuitin which an n-type polysilicon layer is used as a semiconductor layerare used.

In a capacitance type touch panel, since a change in capacitance due toa finger or the like is detected, the width of the scanning electrodes(TX) for the touch panel that performs alternating-current driving isdesirably about 4 to 5 mm. Therefore, the number of scanning electrodes(TX) increases according to an increase in the size of the liquidcrystal display panel.

In the example shown in FIG. 7 , the counter electrodes (CT) of 1280display lines are divided into twenty blocks CT1 to CT20 (one block isconfigured by counter electrodes of sixty-four display lines). Twentycounter electrode wires (CTL) are necessary on each of the left and theright.

The counter electrodes (CT1 to CT20) of the blocks cause image qualitydeterioration when voltage fluctuation is caused by parasiticcapacitance in a display operation. Therefore, it is necessary to reducea resistance value of the counter electrode wires (CTL) that connect thecounter electrodes (CT1 to CT20) of the blocks and the liquid crystaldriver IC (DRV). Since wires are present on the scanning line drivingcircuits (GES) as well, the counter electrode wires (CTL) cannot bewired on the scanning line driving circuits (GES).

Therefore, the counter electrode wires (CTL) are arranged further on thecounter electrode (CT) side than the scanning line driving circuits(GES).

To correspond to the arrangement, in the liquid crystal driver IC (DRV),a video line driving terminal (TAD) connected to a video line (not shownin the figure) is arranged in the center of the display area (AR) of thesemiconductor chip. Terminals (A1 and A2) connected to the counterelectrode wires (CTL) are arranged at both left and right ends of thevideo line driving terminal (TAD).

FIG. 8 is a plan view for explaining a method of driving counterelectrodes divided into a plurality of blocks in another example of theliquid crystal display device applied with the present invention.

The liquid crystal display device shown in FIG. 8 is different from theliquid crystal display device shown in FIG. 7 in that counter electrodeselecting circuits (CTSC) configured to select, with an address decodesystem, the respective counter electrodes (CT1 to CT2) divided intotwenty blocks is incorporated in the inside of the liquid crystaldisplay panel.

In FIG. 8 , driving circuits having a CMOS circuit configuration areused as the counter electrode selecting circuits (CTSC).

Since a method of selecting the counter electrodes (CT1 to CT20) dividedinto the twenty blocks is the address decode system, wires that requirelow resistance are two wires, i.e., a wire (LVcom) for a counter voltage(Vcom) supplied to the counter electrodes (CT1 to CT20) and a wire(LVstc) for a touch panel scanning voltage (Vstc).

In this embodiment, as the touch panel scanning voltage (Vstc), avoltage higher than the counter voltage (Vcom) by 5 to 10 V is suppliedas a direct current. Selection of a scanning place is performedaccording to an address signal (addres) supplied via an address signalline (Saddres). The counter voltage (Vcom) or the touch panel scanningvoltage (Vstc) is switched and output to the counter electrode (CT) of aselected block, which is used as the scanning electrode (TX) as well,according to a touch panel scanning signal (STC).

Even when the number of divisions of the counter electrode (CT)increases, a wire to be added is only the address signal line (Saddres).It is possible to increase the number of divisions of the counterelectrode used as the touch panel scanning electrode while keep onsuppressing an increase in left and right frames of the liquid crystaldisplay panel.

FIG. 9 is a block diagram showing a configuration example of the counterelectrode selecting circuits (CTSC) shown in FIG. 8 . As shown in FIG. 9, the counter electrode selecting circuit (CTSC) includes addressdecoder circuits DEC1 to DEC20 and selection circuits SCH1 to SCH20.

In the liquid crystal display device shown in FIG. 8 , the counterelectrodes (CT) for sixty-four display lines are electrically connectedon the inside of the liquid crystal display panel to form one block and1280 display lines are divided into twenty such that the scanningelectrodes (TX) of the touch panel are arranged at a 5 mm pitch. Thecounter electrodes (CT1 to CT20) divided into twenty and the addressdecoder circuits (DEC1 to DEC20) are allocated in a one-to-one relation.Since the number of divisions is twenty blocks, five 5-bit addresssignal lines (Sadd) are necessary.

The counter electrodes of one block, i.e., the counter electrodes (CT)equivalent to sixty-four lines selected according to the address signal(addres) perform alternating-current driving according to the touchpanel scanning signal (STC). The other counter electrodes (CT) output acounter voltage.

FIG. 10 is a circuit diagram showing a circuit configuration of anexample of the selection circuit (SCH1 to SCH20) shown in FIG. 9 .

The selection circuit shown in FIG. 10 inputs an output (DECO) of theaddress decoder circuits (DEC1 to DEC20) and an inverted signal of thetouch panel scanning signal (STC) inverted by an inverter (INV1) to aNOR circuit (NOR1), inverts an output of the NOR circuit (NOR1) with aninverter (INV2), and inputs the output to a switch circuit (SW) tothereby select the touch panel scanning voltage (Vstc) or the counterelectrode (Vcom) and output the voltage to the counter electrodes (CT1to CT20) of the blocks.

Consequently, when one of the address decoder circuits (DEC1 to DEC20)is selected, the selection circuit switches the touch panel scanningvoltage (Vstc) and the counter voltage (Vcom) and outputs the voltagesto the counter electrodes of the blocks according to a touch panelscanning signal (STC).

That is, in the selection circuit shown in FIG. 8 , the output of theNOR circuit (NOR1) is at an H level when the output (DECO) of theaddress decoder circuits (DEC1 to DEC20) is at a Low level (hereinafter,L level) and the touch panel scanning signal (STC) is at a High level.(hereinafter, H level). Therefore, the switch circuit (SW) selects thetouch panel scanning voltage (Vstc). When the touch panel scanningsignal (STC) is at the L level or the output (DECO) of the addressdecoder circuits (DEC1 to DEC20) is at the H level, the output of theNOR circuit (NOR1) is at the L level. Therefore, the switch circuit (SW)selects the counter voltage (Vcom).

FIG. 11 is a circuit diagram showing a circuit configuration of anexample of the address decoder circuits (DEC1 to DEC20) shown in FIG. 7.

As shown in FIG. 11 , concerning each of five address signals (addres),the address signal or an inverted signal obtained by inverting theaddress signal with an inverter is input to the address decoder circuits(DEC1 to DEC20). The address decoder circuits (DEC1 to DEC20) decode theaddress signal or the inverted signal on the basis of combinations ofthe five address signals (addres) and inverted signals of the fiveaddress signals (addres).

The address decoder circuit shown in FIG. 11 inputs an address signal(add) of a predetermined combination of the five address signals(addres) and the inverted signals of the five address signals (addres),which are input to the address decoder circuit, to NAND circuits (NAND1and NAND2), inputs outputs of the NAND circuits (NAND1 and NAND2) to aNOR circuit (NOR2), and inverts an output of the NOR circuit (NOR2) withan inverter (INV3) to obtain an output (DECO) of the address decodercircuit. Therefore, in the address decoder circuit shown in FIG. 11 ,when a combination of address signals coincides with a combination ofaddress signals set in the address decoder circuit, a voltage at the Llevel is output as the output (DECO) of the address decoder circuit.When the combination of address signals does not coincide with thecombination of address signals set in the address decoder circuit, avoltage at the H level is output as the output (DECO) of the addressdecoder circuit.

FIG. 12 is a diagram for explaining driving waveforms during touch paneldetection and during pixel writing in the touch panel-incorporatingliquid crystal display device.

A in FIG. 12 indicates a voltage waveform of the touch panel scanningvoltage (Vstc) supplied to the counter electrode (CT11) in 641st to704th display lines of an eleventh block among the counter electrodesdivided into twenty blocks. B in FIG. 12 indicates a waveform of a videovoltage supplied to the video lines (DL) in odd number rows. C in FIG.12 indicates a waveform of a video voltage supplied to the video lines(DL) in even number rows. D in FIG. 12 indicates a gate signal suppliedto a gate electrode of a thin-film transistor in the 641st display linevia a 641st scanning line (GL). T1 indicates a touch position detectionperiod and T2 indicates a pixel writing period.

The touch position detection period (T1) is set to a period other thanthe pixel writing period (T2) in order to prevent the influence ondisplay. In the touch position detection period (T1), in order toincrease detection sensitivity, a plurality of times of scanning isperformed by the scanning electrode (TX) in the same place, i.e., inFIG. 12 , the touch panel scanning voltage (Vstc) is supplied to thecounter electrode (CT11) of the eleventh block a plurality of times.Within the pixel writing period (T2), the touch panel scanning voltage(Vstc) is not supplied and the counter voltage (Vcom) is supplied to thecounter electrode (CT11) of the eleventh block.

FIG. 13 is a diagram for explaining timings during touch panel detectionand during pixel writing in the touch panel-incorporating liquid crystaldisplay device.

A in FIG. 13 indicates pixel writing timing from a first display line toa 1280th display line in a pixel writing period (T4) of one frame. B inFIG. 13 indicates touch panel detection timing in the counter electrodes(CT1 to CT20) of the blocks divided into the twenty blocks.

As shown in FIG. 13 , a counter electrode in an arbitrary display lineis caused to function as the scanning electrode (TX). A scanningoperation during touch panel detection is performed in a place differentfrom a place of gate scanning for performing pixel writing. In FIG. 13 ,T3 indicates a blanking period, VSYNC indicates a verticalsynchronization signal, and HSYNC indicates a horizontal synchronizationsignal.

In the liquid crystal driver IC (DRV) in this embodiment, among aterminal group arranged on one side of the display area (AR) of thesemiconductor chip, the video line terminal (TAD) connected to the videoline DL is arranged in the center and the terminals (A1 and A2)connected to the counter electrode wires (CTL) are arranged at left andright ends of the video line terminal (TAD).

In the capacitance type touch panel, in order to detect a change incapacitance due to a finger or the like, the width of a scanningelectrode for performing alternating-current driving is desirably about4 to 5 mm. Therefore, the number of scanning electrodes increasesaccording to an increase in the size of the liquid crystal displaypanel.

In the current liquid crystal display panel for portable mobile, thedimension in the longitudinal direction is 120 mm because of a requestfor a 5.5 inch display area. Therefore, if the counter electrode (CT) isdivided at width of 5 mm, twenty-four counter electrodes are formed. Onthe other hand, for the current smart phone, WVGA (480RGB×800) of a 4inch class is generally used and the dimension in the longitudinaldirection is 90 mm. Therefore, if the counter electrode (CT) is dividedat width of 5 mm, eighteen counter electrodes are formed.

Therefore, in the liquid crystal driver IC (DRV) in this embodiment, theterminals (A1 and A2) connected to the counter electrode wires (CTL) aretwenty-four terminals to be adaptable up to a 5.5 inch liquid crystaldisplay panel.

Further, in the liquid crystal driver IC (DRV) in this embodiment, thenumber of terminals in use used for connection to the counter electrodewires (CTL) can be switched in a range of one to twenty-four to beadaptable to liquid crystal display panels including various numbers ofcounter electrodes.

As explained above, in order to prevent image quality deterioration, thecounter electrode wires (CTL) need to have low resistance. Therefore, inthe liquid crystal driver IC (DRV) in this embodiment, the terminals A1and A2 having the same function are provided at the left and right endsof output terminals of the semiconductor chip to make it possible tosupply power to the counter electrode (CT) from both the sides.

In FIG. 14 , a connection example of the terminals (A1) of the liquidcrystal driver IC (DRV) in this embodiment connected when the dividedcounter electrodes (CT) are directly driven is shown.

Note that, in FIG. 14 , a plurality of terminals (terminals A1) on theleft side in a terminal group formed on a side on the display area (AR)side of the semiconductor chip forming the liquid crystal driver IC(DRV) in this embodiment is shown.

As explained above, in the liquid crystal driver IC (DRV) in thisembodiment, the number of terminals in use used for connection to thecounter electrode wires (CTL) can be switched in a range of one totwenty-four corresponding to the scanning electrodes TX1 to TX24.However, in FIG. 14 , the twenty ends of the scanning electrodes TX1 toTX20 are used. The right side among the terminal group formed on theside on the display area (AR) side of the semiconductor chip forming theliquid crystal driver IC (DRV) in this embodiment has the sameconfiguration.

In FIG. 14 , the counter electrode wires (CLT) connected to the counterelectrodes CT1 to CT20 are connected to the respective terminals of thescanning electrodes TX1 to TX20.

The terminals for performing touch position detection output the touchpanel scanning voltage (Vstc) and the other terminals output the countervoltage (Vcom), for example, at timings shown in FIGS. 12 and 13 .

In FIG. 15 , a connection examples of the terminals (A1) of the liquidcrystal driver IC (DRV) in this embodiment connected when the counterelectrode selecting circuits (CTSC) shown in FIG. 8 are used.

In the liquid crystal driver IC (DRV) in this embodiment, a data valueof a register on the inside is switched, whereby the terminals of thescanning electrodes TX1 to TX12 are fixed as terminals for outputtingthe touch panel scanning voltage (Vstc) and the terminals of thescanning electrodes TX13 to TX24 are fixed as terminals for outputtingthe counter voltage (Vcom) to output the touch panel scanning voltage(Vstc) and the counter voltage (Vcom) to the counter electrode selectingcircuits (CTSC) shown in FIG. 8 .

In the case of FIG. 15 , output impedance of output terminals of theliquid crystal driver IC (DRV) in this embodiment is 100Ω. Therefore, byconnecting twelve output terminals in parallel for each of the touchpanel scanning voltage (Vstc) and the counter voltage (Vcom), it ispossible to reduce output impedance of the terminals for outputting thetouch panel scanning voltage (Vstc) and the counter voltage (Vcom) to100Ω÷12=8.3Ω.

In the liquid crystal driver IC (DRV) in the past, the terminals foroutputting the control signal for driving the scanning line drivingcircuits (GES) are arranged in the terminal group formed on the side onthe display area (AR) side (hereinafter referred to as output side) ofthe semiconductor chip forming the liquid crystal driver IC (DRV).

However, since the counter electrode wires (CTL) need to have lowresistance, the terminals (A1 and A2) connected to the counter electrodewires (CTL) need to be arranged on the side on the outside side of thesemiconductor chip forming the liquid crystal driver IC (DRV).

In addition, if the terminals for outputting the control signal fordriving the scanning line driving circuits (GES) are arranged on theside on the output side of the semiconductor chip forming the liquidcrystal driver IC (DRV), a chip size increases, leading to an increasein chip costs.

Therefore, in this embodiment, the terminals (B1 and B2) for outputtingthe control signal for driving the scanning line driving circuits (GES)are arranged on the opposite side of the display area (AR) (hereinafterreferred to as input side) of the semiconductor chip forming the liquidcrystal driver IC (DRV).

In FIG. 16 , a connection example of the terminals on the input side ofthe liquid crystal driver IC (DRV) in this embodiment is shown.

In FIG. 16 , TAD denotes a video line terminal, A1 and A2 denoteterminals connected to the counter electrode wires (CTL), B1 and B2denote terminals for outputting the control signal for driving thescanning line driving circuits (GES), C1 and C2 denote terminals towhich detection signals detected by the detection electrodes (RX) of thetouch panel are input, and D denotes terminals to which an input signaland a power supply voltage from the outside are input.

In FIG. 17 , a connection example of the terminals (B1 and B2) arrangedon the input side of the liquid crystal driver TC (DRV) in thisembodiment is shown.

When a gate selection voltage of the thin-film transistors (TFT) of thepixels is represented as VGH and a gate non-selection voltage of thethin-film transistors is represented as VGL, the scanning line drivingcircuits (GES) including the driving circuit having the a-Si singlechannel circuit configuration or the driving circuit having the p-Sisingle channel circuit configuration input a driving signal havingamplitude (VGH-VGL) and perform a gage scanning operation.

Likewise, the address signal (addres) of the counter electrode selectingcircuits (CTSC) including the driving circuit having the CMOS circuitconfiguration is a signal having amplitude (VGH-VGL).

However, voltage levels necessary for an amorphous silicon thin-filmtransistor (a-Si TFT) in which amorphous silicon is used for asemiconductor layer are, for example, VGH=16V and VGL=−13V. Voltagelevels necessary for a polysilicon thin-film transistor (p-Si TFT) inwhich n-type polysilicon is used for a semiconductor layer are, forexample, VGH=11V and VGL=−8V. Therefore, the voltage levels necessaryfor an amorphous silicon thin-film transistor (a-Si TFT) and the voltagelevels necessary for a polysilicon thin-film transistor (p-Si TFT) aredifferent.

The driving circuit having the a-Si single channel circuitconfiguration, the driving circuit having the p-Si single channelcircuit configuration, and the driving circuit having the CMOS circuitconfiguration respectively require different driving waveforms becauseof the circuit configurations. If the respective driving waveforms areoutput at separate output terminals, a chip size increases according toan increase in the number of terminals.

Therefore, in the liquid crystal driver IC (DRV) in this embodiment, therespective driving signals of the driving circuit having the a-Si singlechannel circuit configuration, the driving circuit having the p-Sisingle channel circuit configuration, and the driving circuit having theCMOS circuit configuration incorporated in the liquid crystal displaypanel output from the terminals or the waveforms of the driving signalscan be switched using the same common terminal according to a data valuewritten in the register.

The voltage levels of VGH and VGL can be switched according to a datavalue written in the register to enable one common terminal to cope withthe driving circuit having the a-Si single channel circuitconfiguration, the driving circuit having the p-Si single channelcircuit configuration, and the driving circuit having the CMOS circuitconfiguration.

For example, in FIG. 17 , in a terminal GOUT7 of the terminals (B2) onthe right side of the liquid crystal driver IC (DRV), when anincorporated circuit is the driving circuit having the a-Si singlechannel circuit configuration (a-Si in FIG. 17 ), a “gate clock signal(VG10)” is output. When the incorporated circuit is the driving circuithaving the p-Si single channel circuit configuration (p-Si in FIG. 17 ),the terminal is “not used”. When the incorporated circuit is the drivingcircuit having the CMOS circuit configuration (CMOS in FIG. 17 ), an“address decode signal (Tx_ADR1_R)” is output.

In the in-cell touch panel in this embodiment, the scanning electrodes(TX) are pulse-driven at a voltage of about 4 V to 6 V and a voltagechange in the detection electrodes (RX) is detected.

When parasitic capacitance between the scanning electrodes (TX) and thedetection electrodes (RX) changes because of a finger or the like andthe scanning electrodes (TX) are pulse-driven at a voltage of about 4 Vto 6 V, voltage fluctuation of the detection electrodes (RX) changes.Therefore, it is possible to detect a touch position by measuring thevoltage of the detection electrodes (RX).

Therefore, upper and lower wiring layers and wires on both sides of thewires for the detection electrodes (RX) on the main flexible printedcircuit substrate (MFPC) are shielded by a ground voltage (GND) toprevent the wires from being affected by external noise.

In the liquid crystal driver IC (DRV) in this embodiment, when a touchsense function is incorporated in the liquid crystal driver IC (DRV),input terminal positions for detection signals detected by the detectionelectrodes (RX) are important.

In the liquid crystal driver IC (DRV) in this embodiment, as signals andvoltages input to input terminals (D), there are an input signal 1, aninput signal 2, a power supply, and a GND. The input signal 1 and theinput signal 2 are respectively signals of different interfaces. The twosignals are not simultaneously used. One of the systems is usedaccording to the configuration on the main body side.

Further, in the in-cell touch panel, the wires for the detectionelectrodes (RX) are connected to the main flexible printed circuit board(MFPC) of the TFT substrate (2, SUB1) from the connection flexibleprinted circuit board 53 connected to a substrate (e.g., a glasssubstrate) on the CF substrate (3, SUB2) side by FOG (Film On Glass).Therefore, the wires have to be freely laid out in response to a requestfor an external shape of a product including the main flexible printedcircuit board (MFPC).

Therefore, in the liquid crystal driver IC (DRV) in this embodiment, oneset of the input terminals (C1 and C2) for the detection signalsdetected by the detection electrodes (RX) are provided on each of thesides of the input terminals (D).

The input terminals (C1 and C2) for the detection signals detected bythe detection electrodes (RX) are arranged as shown in FIG. 16 .Therefore, the wires do not cross the scanning line driving circuitsignal wires (GTL) wired to the liquid crystal display panel side andare not affected by noise.

Further, since the terminals having the same functions are arranged onthe left and right, it is possible to select the terminals in useaccording to a request for an external shape of a product. Only one ofthe input terminals (C1 and C2) for the detection signals detected bythe detection electrodes (RX) is used according to a product.

In FIG. 18 , a configuration in which the terminals on the left side(C1) are used as the input terminals for the detection signals detectedby the detection electrodes (RX) is shown. In FIG. 19 , a configurationin which the terminals on the right side (C2) are used as the inputterminals for the detection signals detected by the detection electrodes(RX) is shown.

The invention devised by the inventor is specifically explained above onthe basis of the embodiment. However, the present invention is notlimited to the embodiment. It goes without saying that the presentinvention can be variously changed without departing from the spirit ofthe present invention.

While there have been described what are at present considered to becertain embodiments of the invention, it will be understood that variousmodifications may be made thereto, and it is intended that the appendedclaim cover all such modifications as fall within the true spirit andscope of the invention.

What is claimed is:
 1. A display device comprising: a first substrateincluding a plurality of pixel electrodes, a plurality of commonelectrodes, and a plurality of video lines extending along a firstdirection; a display area including the plurality of pixel electrodesand the plurality of common electrodes; and a chip capable of supplyinga common voltage and a touch driving signal to the plurality of commonelectrodes, and video signals to the plurality of video lines, whereinthe plurality of common electrodes serve as a counter electrode of theplurality of pixel electrodes and as a touch driving electrode, the chiphas a first long side and a second long side, the first long side andthe second long side extending along a second direction, the chipincludes a row of first terminals, each of which is connected to acorresponding one of the plurality of common electrodes, and a row ofsecond terminals, each of which is connected to a corresponding one ofthe plurality of video lines, and at least an end of the first long sideis closer to the row of the first terminals than the row of secondterminals.
 2. The display device according to claim 1, furthercomprising; a plurality of pixel transistors, each of which is connectedto a corresponding one of the plurality of pixel electrodes; and aplurality of scanning lines capable of supplying a scanning voltage tothe pixel transistors, wherein the first substrate includes a scanningline driving circuit capable of supplying the scanning voltage to theplurality of scanning lines.
 3. The display device according to claim 2,wherein a plurality of scanning line driving circuit wirings are formedon the first substrate and electrically connected to the scanning linedriving circuit.
 4. The display device according to claim 1, furthercomprising a main flexible printed circuit board electrically connectedto the chip.